VimでBad Apple!!

こんにちわ。
[ゴリラ.vim](https://gorillavim.connpass.com/)を運営している[ゴリラ](https://twitter.com/gorilla0513)です。

最近Vimのプラグインを作るのにハマっています。先日も[docker.vim](https://qiita.com/gorilla0513/items/1c756fd3aba8e68b9575)というVimからdockerコンテナを操作するプラグインを作りました。
良かった試してみてください。

さて、本題ですがみなさんは`Bad Apple!!`をご存知でしょうか？
多分ニコニコユーザならほぼ知っているのではないかと思います。
そうです。かの有名な動画です。

その動画のAscii版があり、それならVimで再生できるのでは？と思い帰りの電車の中で作ってみました。

<a href="https://github.com/skanehira/badapple.vim"><img src="https://github-link-card.s3.ap-northeast-1.amazonaws.com/skanehira/badapple.vim.png" width="460px"></a>

# どんな感じ？
こんな感じです。
すこしちらつきますが、まぁ見れなくはないかなと言った感じです。

![bad_apple.gif](https://qiita-image-store.s3.ap-northeast-1.amazonaws.com/0/66178/b2ec2863-60c4-413e-1d89-c9b1c94e7e95.gif)

# 仕組みは？
とっても簡単です。簡潔に言うとテキストファイルを読み込み、フレーム分のテキストを配列に格納して、あとはfor分で回して画面に描写します。

もう少し細かく解説します。

## Asciiテキストファイルの読み込み
Bad Apple!のAsciiテキストファイルは[こちら](https://github.com/Chion82/ASCII_bad_apple)にあるので、それを借用しました。
<details>
<summary>テキストファイル</summary>
```
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```
</details>

見て分かる通り、`SPLIT`で区切っています。なので、`SPLIT`までを1フレームとしてます。
処理は次になります。

```vim
" read file to create frames
function! s:read_file() abort
    let file = globpath(&rtp, 'resources/badapple.txt')
	" 全frameを格納
    let frames = []
	" 1frame分のテキストを格納
    let frame = []

    for line in readfile(file)
		" 現在行に`SPLIT`が含まれていなければframeに追加
        if line !~# "SPLIT"
            call add(frame, line)
        else
			" frameをframes追加
            call add(frames, frame)
            let frame = []
        endif
    endfor

    return frames
endfunction
```

なぜframeを配列にしているかというと、vimではバッファにテキストを書き込む`setline()`とpopup windowのバッファに書き込む`popup_settext()`という関数がありますが、
引数に配列を渡すと配列の1要素が1行として画面に出力します。そうすることで改行文字をわざわざ追加しなくて済むのでコードがスッキリします。

## 画面に出力する
フレームを作る関数を用意したので、それを使用してフレーム情報を変数に格納し、forで1frameずつ画面に出力します。

```vim
for frame in frames
	" ここで画面にframeを出力する
	call popup_settext(winid, frame)
	" redraw!で画面を再描写する"
	redraw!
	" 一瞬で出力が終わってしまうので少し待つ
	sleep 50ms
	" qで終了できるように`getchar()`で入力した文字を取得
	" キー入力を待たないように、引数に`0`を渡す
	let key = getchar(0)
	if key ==# 113
		break
	endif
endfor
" for分を抜けたらウィンドウを閉じる"
call popup_close(winid)
```

## まとめ
動画をAsciiテキストに変換して、フレームを定義すれば、どんなものでも同じようなロジックでVim再生できます。
興味ある方はぜひチャレンジしてみてください。